The present invention relates to apparatus for examining, measuring and recording physiologic processes in biological bodies or parts of bodies by use of electromagnetic fields. Specifically, the body or parts of the body are exposed to electromagnetic alternating fields generated by a transmitting device and the resulting magnetic phenomena in the body are measured at its surface.
Measuring apparatus for the examination of physiological processes in biological objects was already proposed in German Auslegeschrift No. 2,255,757. In this publication, apparatus was disclosed in which the processes were to be identified and measured by measurement of the electromagnetic as well as the electrical component of the primary field. However, the measurement of these two components cannot yield adequate results, since in order to do so both of the field strengths must relate to the same enclosed space. If they do not relate to the same space they cannot be put into a mathematical relationship to each other, as is required if the impedance of the space is to be calculated.
Further, in known apparatus the distance between the object to be measured and the measuring system may affect the measuring results to a greater extent than do the physiological processes in the body. Movement of the body also distorts the result and can mask the changes resulting from physiological causes. It must also be considered that physiological processes internal to the body cause changes in the order of 1/1000 of the effective resistance of the body, thereby having only little influence on the primary field. The primary field does not vary greatly as a function of the impedance of the body, since the resistance to radiation of the proposed arrangement is relatively low ohmic.